| /* IdFunction.java -- |
| Copyright (C) 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.xml.xpath; |
| |
| import java.util.Collection; |
| import java.util.List; |
| import org.w3c.dom.Node; |
| |
| /** |
| * The <code>id</code> function selects elements by their unique ID. |
| * When the argument to id is of type node-set, then the result is |
| * the union of the result of applying id to the string-value of each of the |
| * nodes in the argument node-set. When the argument to id is of any other |
| * type, the argument is converted to a string as if by a call to the string |
| * function; the string is split into a whitespace-separated list of tokens |
| * (whitespace is any sequence of characters matching the production S); the |
| * result is a node-set containing the elements in the same document as the |
| * context node that have a unique ID equal to any of the tokens in the |
| * list. |
| * |
| * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a> |
| */ |
| public final class IdFunction |
| extends Pattern |
| { |
| |
| final Expr arg; |
| |
| IdFunction(List args) |
| { |
| this((Expr) args.get(0)); |
| } |
| |
| public IdFunction(Expr arg) |
| { |
| this.arg = arg; |
| } |
| |
| public boolean matches(Node context) |
| { |
| Object ret = evaluate(context, 1, 1); |
| return !((Collection) ret).isEmpty(); |
| } |
| |
| public Object evaluate(Node context, int pos, int len) |
| { |
| Object val = arg.evaluate(context, pos, len); |
| return _id(context, val); |
| } |
| |
| public Expr clone(Object context) |
| { |
| return new IdFunction(arg.clone(context)); |
| } |
| |
| public String toString() |
| { |
| return "id(" + arg + ")"; |
| } |
| |
| } |